A generic internal combustion piston engine known from U.S. Pat. No. 5,088,488 comprises roller tappets of the pre-cited type and an anti-rotation device in the form of an anti-rotation bridge of the pre-cited type. The anti-rotation bridge is made of a polymer material, e.g. polyamide, and is fixed to a component of the internal combustion piston engine.
For facilitating mounting of the roller tappets on the internal combustion piston engine, the spacing dimension of the flattened portions on the roller tappets is larger than the spacing dimension of the inner surfaces on the anti-rotation bridge, so that an overlap is created, i.e. the roller tappets are clamped in the anti-rotation bridge. This is useful and of advantage for the mounting of the roller tappets on the internal combustion piston engine but leads to undesired higher friction in the subsequent operation of the engine.